Had some guys come by today and install the minisplit system. If you're not familiar, then you've probably never lived in a shipping container in Afghanistan. This is a small heat pump that mounts to a space with very little structural modification. There's a 3-inch hole in the wall of the workshop.
The aptly named indoor unit is the air handler. It's mounted up on the wall. The equally aptly named outdoor unit contains the condenser. It's all physics.
The best part is that it works great and now I can work in the shop all year long.
The vision is becoming clear. At least it's a comfortable temperature.